dx1ng said:
When I first saw posts speculating about WCBS ground wave reception at Miami, I did some calculations based on the FCC engineering charts, and found that there should actually be a very weak WCBS signal of a few microvolts at Miami. WCBS is helped by it's tall tower, which gives it an effective power of around 100 kw compared to stations with normal (1/4 wave) towers. Even so, I don't think any portable would be able to pick the signal up... it would take a good comunications receiver with a really good antenna. Any farther north along the coast than West Palm Beach, and the WCBS signal would have to cross a lot of land, and simply couldn't make it. Even going just as far north as Fort Pierce, and you have about 150 miles of Virginia and North Carolina land for the WCBS signal to cross... that would really kill the signal. It would be even worse farther north on the Florida coast. And we haven't even considered interference... if WZAB is on the air on 880 from the Miami area, there's no chance of hearing WCBS. And Cuba too... remember Cuban stations are a LOT closer, and they have at least a partial water path. And I don't know what else might propagate that way from the Caribbean.
It's about 1100 miles from New York City to Miami.... that's a BIG difference from the 450 miles or so separating New Orleans and Tampa (or the 350 to 400 miles between New York City and the Outer Banks).
Simply said, even though most sky wave occurs between 2 hours before sunset and 2 hours after sunrise, if WCBS is heard in Florida it is via skywave.
It makes sense because I even asked the question recently wondering how it's possible for a station from New York in which can't be heard just inland in North Carolina to be heard somewhere on the coast more south even though both locations are in the exact same direct path from the source of the New York station. Someone attempted to explain that the signal
regains strength once back out on the salt water but, to me, that seemed to defy the laws of physics. You don't get something from nothing. That's why I see your point, dxing.
A couple of posters here have said they've heard WCBS in the daytime, one right on the water at Miami Beach and the other on the intercoastal in Daytona Beach. Like you say, maybe it was either a skywave involved and/or an exceptional receiver?